Serena Williams has been fined $10,000 (£6,000) by US Open organisers for her tirade towards a line judge during her semi-final defeat by Kim Clijsters.
The American lost her cool after being foot-faulted at the end of the contest.
Officials, who also fined Williams $500 for racquet abuse in the same match, said further penalties could be imposed once an investigation had taken place.
WTA Tour chief Stacey Allaster called the 28-year-old's conduct both "inappropriate and unprofessional".
Allaster's statement continued: "No matter what the circumstances, no player should be allowed to engage in such behaviour without suffering consequences…